Anemia in chronic heart failure patients: comparison between invasive and non-invasive prognostic markers

Background: The prognosis of chronic heart failure (CHF) remains poor despite advances in medical management. Several different variables determine prognosis. Recently anemia has emerged as an independent prognostic variable in the evaluation of CHF. It is therefore important to analyze the role of anemia in patients with mild to severe CHF already well characterized by hemodynamic, echo- Doppler, and cardiopulmonary exercise testing. Objective: We performed this study to evaluate, in a large general cohort of CHF patients, the frequency of anemia and its correlation with their clinical profile. We assessed the prognostic value of anemia in relation to other known prognostic variables. Methods: Two-dimensional echocardiography, right heart catheterization, cardiopulmonary tests and laboratory examinations were performed in a population of 980 consecutive patients with CHF (53±9.4 years, 85% male, LVEF 25±8%; 45% with NYHA class III-IV). A hemoglobin (Hb) concentration less than 12 g/dl was used to define anemic patients. The primary end point was cardiac death or urgent heart transplantation. Results: Nineteen percent of patients were anemic. These patients had a lower body mass index (24±3 vs. 25±4 Kg/m2 p <0.0004), a worse functional class (64% were in NYHA class III-IV vs 41% in the non-anemic group, p <0.0001), poorer exercise capacity (12.4 vs. 14.8 ml/kg/min peak VO2, p <0.0001) and increased right (7±5 vs. 5±4 mmHg, p <.0004) and left (21±9 vs. 19±10 p <0.007) ventricular filling pressures. During a 3-year follow-up cardiac deaths occurred in 236 (24%) and 52 (5%) of patients received an urgent heart transplant. On univariate regression analysis anemia was significantly correlated with these “hard†cardiac events (39% of anemic patients vs 27% of non-anemic patients). By multivariate logistic regression analysis different prognostic models were identified using non-invasive, with or without peak VO2, or invasive parameters. The prognostic model including anemia (AUCROC: 0.720) showed similar accuracy in predicting cardiac events to other prognostic models with peak VO2 (AUCROC: 0.719) or invasive variables (AUCROC: 0.719). Conclusions: The present study demonstrates that anemia in CHF patients is associated with prognosis, worse NYHA functional class, exercise capacity and hemodynamic profiles. The relationship between anemia and mortality is independent of other simple non-invasive prognostic factors. Prognostic models with more complex or invasive independent predictors did not increase the accuracy to predict cardiac mortality or the need for urgent transplantation.